title: Change in antimicrobial susceptibility of Mycoplasma gallisepticum field isolates.
abstract: This study compares the antimicrobial susceptibility over time between two groups of Mycoplasma gallisepticum (MG) isolates from the same geographical area. Minimum inhibitory concentration of 13 antimicrobials was determined against two groups of MG isolates from chickens. Group 1 strains (n=22) were isolated in 2004-2005 while group 2 strains (n=7) were isolated in 2007-2008. Minimum inhibitory concentration 50 for group 1 versus group 2 was 4/4, 0.5/0.5, ≤ 0.031/≥ 64, ≤ 0.031/2, ≤ 0.031/0.125, 1/0.5, 1/1, ≤ 0.031/≤ 0.031, ≤ 0.031/2, ≤ 0.031/2, 1/4, ≤ 0.031/0.062, and 0.062/2 μg/ml against gentamicin, spectinomycin, erythromycin, tilmicosin, tylosin, florfenicol, thiamphenicol, tiamulin, ciprofloxacin, enrofloxacin, chlortetracycline, doxycycline, and oxytetracycline, respectively. There was a statistically significant increase in resistance of group 2 to erythromycin, tilmicosin, tylosin, ciprofloxacin, enrofloxacin, chlortetracycline, doxycycline, and oxytetracycline. This dramatic increase in resistance against 8 antimicrobials belonging to three different families of antimicrobials in a relatively short period of time appears to be rare and of concern. The cause of this increased resistance observed in group 2 of MG isolates was not determined and should be further investigated. Monitoring of MG field strain susceptibility is highly recommended to implement successful treatment and prophylaxis programs in endemic areas.
authors.affiliation: Faculty of Veterinary Medicine, Jordan University of Science and Technology, Irbid 22110, Jordan. saadgh@just.edu.jo
authors.forename: Saad
authors.initials: S
authors.lastname: Gharaibeh
authors.forename: Mohammad
authors.initials: M
authors.lastname: Al-Rashdan
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D002645:Chickens; D004224:Diterpenes / Q000494:pharmacology / Q000627:therapeutic use; D018432:Drug Resistance, Multiple; D008826:Microbial Sensitivity Tests; D009175:Mycoplasma Infections / Q000188:drug therapy / Q000382:microbiology / Q000662:veterinary*; D045686:Mycoplasma gallisepticum / Q000187:drug effects* / Q000302:isolation & purification; D011201:Poultry Diseases / Q000188:drug therapy* / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents; D004224:Diterpenes; C014224:tiamulin